Classic installer weirdness

Weird experience just now: I installed the latest classic Mac OS update (9.2.2) while running Mac OS X. I doubleclicked and ran the installer; it quit all processes IN MY MAC OS X session (except the Dock) and then logged out OS X when it was done. Surely it could have just dumped me back into X and made me restart the Classic process. Frankly, though, I’m amazed it worked at all.